某高速公路跨线桥裂缝成因分析

Analysis of Reasons for Cracks of a Box Beam Bridge

针对某高速公路一座跨线桥出现的裂缝 ,通过数值模拟得出剪力滞效应是该桥裂缝形成的主要因素 .通过计算发现支座沉降和伸缩缝失效 ,对于箱梁截面正应力有明显加强 ,剪力滞系数横向分布曲线明显变陡 ,表明此连续箱梁桥对支座沉降和伸缩缝失效很敏感 .

The formation of cracks on a box beam bridge is discussed. It is found that shear lag is the main reason of crack formation using FEM. According to the fact, support subsidence and expansion joints failure are also considered in computation, and the two reasons have good contribution to the stress of beam. The curve line of shear lag coefficient becomes steeper. It is showed that the continuous beam bridge is very sensitive to support subsidence and expansion joints failure. At the end, other reasons such as construction technology and facture mechanics theory are also discussed.